Object disappears when trying to simulate Soft Body physics
Checked out the file and found the culprit : Cartman is the bugger.

Aside from some wrong normals, the biggest problem is overlapping geometry.

Very heavy/bad for simulations that base on calculations using the geometry data of an object. 

Suggestions to fix the problem:


Retopologize the object, reducing the vertex count and at the same time leads to not only a cleaner mesh, but a faster simulation.
Fixing the geometry of the object to have no overlapping parts anymore. If possible reduction of vertices wherever possible.


While both will take time, i'd go with the first one, as it would be training, and in a way easier, as you work from outside and around. While the latter would take longer i believe alone due to the very tight geometry in the leg/feet (bottom) part.

Without cleaning the the object, i don't think you should try getting the soft-body simulation to work, as all the fine tuning to get the object react as should won't compensate for the underlying problem.

There is a 3rd option, in case you just want the figure to fall in the glass.
No deformation like soft-body possible, but bouncing would work.
Rigid Body Simulation, making the figure an active object and both glass objects passive (important to set all objects to "Mesh" shape), will at least give you the experience of an Erik Cartman falling in a glass-jar.